Abstract
In this study, composites based on poly(lactic acid) (PLA)/talc were prepared at different compositions by melt mixing in a twin screw extruder. The effect of a nucleating agent, talc, on the crystallization behavior, rheological and morphological properties of PLA was investigated. DSC results showed that the addition of the mineral filler in the range between 1 and 5 wt. % to the PLA matrix increases the degree of crystallinity. This finding shows that talc acted as a nucleating agent for PLA during the processing stage. The composites morphology was also studied using a scanning electron microscope (SEM). The micrographs showed that a good dispersion of talc was achieved in all compositions analyzed. The rheology of PLA/talc composites was evaluated with the dynamic mode and correlated with the aforementioned observed morphology. The results showed that the addition of the mineral filler to the PLA matrix decreased system viscosity, thus highlighting the filler's lubricant effect. As talc content increased, system's viscosity also increased, providing material with higher elastic behavior. Thermal analysis showed that the composition of 3 wt.% of talc added to polymer matrix seems to be interesting with regard to the need of articles possessing good dimension stability.
Highlights
It was observed that poly(lactic acid) (PLA) presents a higher viscosity in the whole range of the explored frequency and, as talc is added to the polymer matrix, a decrease in viscosity values was observed
The rheological measurements showed a Newtonian behavior of the PLA and PLA composites up to 10 rad.s–1, and all the materials became pseudoplastic melts
The addition of 1 wt.% of talc resulted in a decrease of the viscosity values due to the lubricant effect of the mineral filler on the PLA chains
Summary
Thermal analysis showed that the composition of 3 wt.% of talc added to polymer matrix seems to be interesting with regard to the need of articles possessing good dimension stability. (lactic acid) (PLA) is a well-known biodegradable for semicrystalline polymers in order to accelerate crystallization rate. It acts lowering the surface free aliphatic polyester resin (Figure 1) and it is widely used for so-called simple applications, such as cups, energy barrier related to nucleation and, initiates crystallization at higher temperature upon cooling[8,9]. More advantageous applications of the Several chemicals suitability as NAs for PLA has been evaluated and talc has been widely used in such environmentally friendly resins are under development applications[9]. It’s important to be aware of the potential reduction in overall mechanical properties applications is severely limited by its low glass transition temperature (Tg), which is around 60 °C
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